It is known that at sea use is made of various types of underwater vehicles, either for civilian or military purposes, which are put into the water and recovered from the side of ships equipped for this purpose.
The operations of launching and recovering such vehicles always prove particularly difficult. However, because of the difficulties of manoeuvring them due to the impossibility of maintaining a stable relative position between the waterborne vehicle and the ship because of the wave motion which brings about oscillations of both the vehicle and the ship. Such variation in the relative position of the vehicle with regard to the ship both on the horizontal plane and on the vertical plane therefore hampers the operations for gripping the vehicle, making it very often necessary to resort to putting personnel into the water to perform directly the task of attaching the hook of a hoisting crane to the point of attachment of the vehicle. This operation involves, given the proximity to the side of the ship, hazardous conditions and high risks for such personnel whose presence in the water will be particularly necessary under bad weather and rough sea conditions which obviously bring about a further increase in such risk.
There are known certain conventional solutions which provide for attaching the vehicle by means of a hook located at the end of a rope leading to the winch of a crane. Such solutions, however, not only do not make it possible to grip the vehicle, but also pose a disadvantage because of the fact that at the time of hoisting the vehicle from the water the latter is not rigidly linked and therefore may oscillate and/or rotate around the vertical axis, thus increasing the difficulties of handling in order to transfer it to the stowage point aboard the ship. The handling personnel must in this case secure the vehicle using other ancillary means, for example ropes, to avoid or reduce such oscillation and rotation.
This, creates other operational difficulties and risks, particularly when the ship is undergoing severe oscillation.